CA2022911A1 - Master batch for production of toners used in electrophotography - Google Patents

Abstract

Abstract of the Disclosure There is disclosed a method of producing a master batch for the production of toner particles used in electrophotography, which comprises:
(a) preparing a resin solution;
(b) preparing a mixture which has a dye or a pigment finely dispersed in the resin solution; and (c) removing the solvent from the mixture.
There is also provided a method of producing toner particles for use in electrophotography, which, in addition to the above steps (a), (b) and (c) for the preparation of a master batch, further comprises:
(d) adding a further amount of a second binder resin to the master batch together with an effective amount of an additive when necessary, to form a second mixture, and kneading the second mixture to a composition; and (e) crushing the composition to toner particles.

Description

' 90 ~1~/02 22 30 ~OB 532 78f33 MAKINO ~ COMPANY 1~ o4/~47 2t~X2~

MASTER BATCH FOR PRODUCTIO~ OP TONERS
_ _ USE9 IN EL~CTROPHOTOGRAPHY _ _ BACKGROU~D o~ e INYENTION

Piald of tha Invention Shis invention relates to a master bàtch for the p~oduction of toner partlcle~ used in electroPhotograPhY, and production of toner partlcles using such a master batch.

DescriPtion of the Prior Art An electrophotographic process is well kno~n wherein an electrostatic image i~ formed on a photoconductor, and the electrostat3c i~ge is then developed with a devsloper which contains toner particles, to providc a tonsr image.
and then the tonor i~ag~ is transferred and fixed on a substrate, Two methods are w~ll known for develoPing an electro-s ta tic Ima~e on a photocond~ctor: a one-compOnsnt developing method ~nd a two-component developin~ ~ethod. The two-co~ponent dsveloper is composed o~ toner particl~s and carrier particles, and now widely used in a magnetic brush method, In a mul ~lcolor or ful I oolor electroPhotographic ~0 process which ha~ been very recently put to practical use, a full color tonar ImA~e is produced by forming primary color toner ima~es In laYers sequently on a substrate, and accordingly th~ tho-co~Ponent devcloping ~ethod are mainly eMployed ;n the proc~ss.
In general, triboelectricitY of toner partioles has a ' gO lfl/~2 22 31 ~(:)~ 532 7~3~3 MAI:INO & COMPANY 1~lo~5/~47 2~22Q~ ~

great influ8nce upon quality of fixed images either in the one-co~ponent or in the two-co0ponent develol)ing ~ethod.
When tone~ particles used in ~he two-component developing method have an insufficient specific oloctric charse (an electric cha~ge per weighl of toners), Ihe toner particles have an insufficlent electrostatic interaction ~ith the carrier partlcles, so that ~he toner contaminales ths surroundin~ of the develoPing device, or adheres to areas having no images on a photoconductor, to produce fo~ on the resultant fixed Image. On the olher hand. when ~oner particles have an sxcesslvelY large specific electric charge, an insufficlent arount of toner particler, adheres to an electrostatic image, to produce a fixed image ~Ith an in~ufflcient darkness. Thus, ~hen toner particle~
contain a dye or a pigment dispersed unevenly ~herein as particles of varied sizes. there arise problems of unstabllity of i~age darkDess, background contamination or fog on the ima~e, but also of filming of toner psrticles on photocondùctors, In th~, one-component developing method, toner particles ~re ussd whlch contain ma~netic particles therein, and the ton~r particles are charged by mutual friction or by frictlon with daveloping sleeves ~owever, in the one-component developing method, toner particles are apt to 'c,e charged morë unstably and insufficiently than in the tWo-comPonent developing method. Thus, when toner partlcle~ contaln s~ch parlicles as have insufficient specific electric char8e, the resultant fixed images haue a small or varied darkness as well as fog In this way, when toner particles have a Yar i ed specific electric charge, cither in the t~o-comPonent developing ~ethod or the one-component developin method, there arise a nu~ber of undeslrable problems, Therefore it is very important that individual toner particles have varlous additives, in particuldr. a dye or ' ~10 ()~02 22 32 5(:)ô 532 7~63 MAKINO & ~OMPANY 1~l~06/l347 2022~

a pigMent as a charge cont~ol agent, dispersed as finely and evcnly as possible therein so that the individual toner particle~ ars equally electrifi~d, thereby to produce hi~h quality fixed images stablY and constantly However, it is difficult to disperse a dye or a pigment as a charge control agent or a coloring agent finely and evenly in the individual toner p~rticles bY a known conv~ntional method. Su~h a known conventional method of producing toners comPrises admixing a binde~ resin with a 10 dye or a pigmant by an effective agitation t~ form a mixture, melting and kneadin~ the mixture with, for exsmple, a twin screw extruder, a heating kneadsr or a heatin8 roll, and then cooling a~d crushing the mi~ture to a powder When needed, the powde~ is classifled to a desirable particle lS ~ize, and the Powder Is surface-treated with, for example, colloidal silica, so that the powd~r has a high fluidity.
~l~ost all the dyes and pigments which have heretofor been used in the productlon of toners contain at least In part particles having a larger diameter than the desirable diameter of tonqrs, Th~se particles can not be finely dispsrsed in toner particle~ by a convention~l method, wi th ths consequence that the toner particles eontain an insufficient anount of dye or pigment thereln, or it haPpens thst s0~8 of toner particles contain only a single ~5 pa r t I c Io of dye or p i g ~e n t therein.
Shus thqre is proposed an imProved method of the production of toner partioles to obviate such a problem as aboYe mentioned in Japanese Patent Appli ca tion Laid-oPen No. 62-30~59. According to the method, at ~irst. a part of a binder resin. and a full amount of a dye or a pigment are Mixed, melted and kneaded to8ethen, and then cooled and crushed to form a master batch Then the master batch is mixed with the re~ainder of the binder neslnt melted, kneaded. cooled and crushed to provide toner particles.
However, binder reslns generallY have a low polarity, ' 90 ~)~/l)2 22 33 ~lG 5~2 78f33 MAKINO 1~ COMPANY l~t~7/~47 20229~3.

whereas dy~s and pigments generally h~ve a high polarity, so that it is essentially difficult from the chemical standpoint to disPsrse such dyes or pigments finely and ev~nly in the binder resins by melt-kn~ading.
A further method is disclo~ed in Jap~nese Patent APPlication Laid-open No. 61-156054. In the ~ethode at first, a part of a binder resin and a charge control agent are dissolved in an organic solvent, and then the solvent ic removed, to form a mastsr batch. The master batch is then melted and kneaded togeth~r with the remainder of the binder resin, and the mixture is cooled and crushsd to tonor particles, However. this ~ethod needs a la~ge amount of solvent and costs a great deal, since the ch~rge control aent is in gene~sl rar~ly soluble in organic ~olvents.
1~
BRIEP SUMMARY QF THE INVENTION

It ls, ther~fore, an obJect of the i.nv~ntion to provide a method of producing ton~r particles. elther monochroMatic or colored. for use in electrophotograPhy which individually have ~ dye or a pigmcnt evenlY
dlspersed therein as finely divided particles.
It is a further obJect of the invention to provide a master batch suitablY used for the production of such toner particles as above mentioned.
In accordance with t~e invcntion, there is provided a method of prod~cing a ~aster batch for the production of toners used in electrophotography, which eomprises:
(a) prePerin~ a resin solution;
tb) preParing a mixture which has a dye or e pig~ent flnely dispersed in the resin solutioni ~nd (c) re~ovin~ the solvent from the m~xture.
The resin solution is prepared either bY polymerizlng monomera in an organic solvent or by dissolving a binder resin in ~n organic solvent.

9(~ )2 22 34 ~(~6 532 7~63 MA~IN0 & COMPANY ~08/~47 2~22~

Thus, more specifically, in accordanoe with the lnvention, there is provided a method of producing a mas~er b~tch for the production of to~ers used in electrophoto-graphy, which comprises:
(a) polym~rizing monomers in an or~anic solvent to PrePare a resin solution; and (b) prcparing a mixturc which has a dye or a pigment }inely dlsPersed in the resin solution; and (c) removing the solYent from the mixture.
~urther in accordanc~ with the invention. there is provided a method of prod~cing a master batch for the production of toners used in electrophotographY, which compris es:
(a) di~solving a binder resin in an organic solvsnt to PrApsre a resin solution;
tb) milllng and dispersing a dye or a pig~ent in ths resin solution to prePare a mixturs; and (c) removing the solvent from thfi mixture.
There is provided a further method of producing a ~aster batch for the productlon of toner partcl~ used in electrophotography, which comprises:
(a) dissolving a binder r~sin in an organic solven~
to prepare a resin golution:
(b) milling and dispersing a dye or a pi~ment in an or~anic solvent to prsPare a di~perslon; and (c) ~ixing thc resin solution and the dispersion to~ether to prepare a mixture, ~nd removing the solvent fro~ the mixture.
In accordance with the invention, there is also provided a method of producing toner particles for use in electrophoto~r~phy, which, in adition to the stePS (a), (b) and (c) as above s~S fo~th, furth~r comprises:
(d) adding a further amount of a second bindar resin to~ether with an effective amount of an additi~e when necessary, to form a second mixture, and kneading thc so 08/02 22 3~ 532 7863 MAK I N0 & COMPANY (~ ~)09/~)97 2022nll sec~nd mixture to a composition; dnd (e) crushing the composition So toner particle~.
Other features and advantages of the invention will be apparent fr~m the folloNing descr.iption taken in connection wi th the drawines, In which:
~ig. 1 is a graph show;ng the relation between the nu~be~ of copied ~heets prepared using a develoPer according to the invention and the fixed ima8e darkness;
Pig 2 Is ~ grapl~ owln~ the rel~tion betwcon ths number of copied sheets prepared using a develoPer of comparative examples and the fixed i~age darknass;
P~g. 3 is a graph showing the relation bet~e~n the number of copied sheets prepared using a devcloPer according to the invention and a developer of comparative lS exa~ples, respe~tively, and the fixed i~age dar~noss:
~i~. 4 is a ~raPh showlng a distribution of tribo-electrioity of toner particle~ according to the lnvention;
Plg. S is a graph showing ~ distrib~tion of tribo-el~etricity of toner psrticles of comparative examples:
Pig. 6 is a graph showing a dlstribution of tribo-electricity of toner particles accordin~ to the invention and toner particles of co~parative examples, resPectively;
Pig. 7 is a graph showin8 the r~lation betweqn the number of coPied shects prePared u~ing a develoPer according to the inventlon and the fixed i~a~e darkness:
~ig. 8 is a g~aPh showing the relation between the number of copied sheets prepared usin~ a developer of comParative exa~ples and the flxed image darkness;
Fig 9 is a graph showlng a distribution of tribo-electricity of toner particles according to the invention;
Fig. 10 is d grsph shôwin2 a distribution of tribo-electricity of toner particles of comparative examples;
Fig. Il ~s a g~aph shohing the ~elation between the number of eopied sheets prepared using a developer 35 accordlng to the invention and th~ fixed ima~e darkness;

'~0 08~02 22 35 ~06 532 7~63 MA~INO ~ ~OMPANY ~ 010/~47 2022~1~

Pi~. 12 is a graph ~howing the relation between the number of copied sheets prepared using a develoPer of comparative examples and the toner image d~rkness:
Fig. 13 is a graPh showing a distribution of tribo-èlectricity of toner particles accordin~ to ~he invention;and Fi~, 14 is a g~aPh showing a distribution of tribo-electricity of toner particles of comParative examples.
.

DETAI~ED DeSCRlPT10~ ~ THE lNVeNTlON
She bindcr resin used is not specifically limited.
but any resin may be used which i~ known in thc art of toners for use in electroPhotography. There maY be ~entioned as such a binder resin, for instance. a homo-polymers or copolymers of two or more of radical polymeri-zable MOnOmers such as styr~ne, o-Methylsty~ene, m-~ethyl-stYrene, p-methylstyrene, P-chloro~tyrene. vinYI acetate, vinyl propionate, methYl acryl~te, e~hyl acrYlate, n-butyl acrylate, isobutyl ecrYlate. n-octyl acrylate. dodecyl acrylate, 2-ethylh~xyl acrYlate, stea~yl scrylate. ~-chlorostearyl acrylate, phenyl acryalte, methYI ~-chloro-acrylate, methyl ~ethacrYlate. ethyl methacryl~te. proPYI
methacrylate, n-butyl methacrYlate1 isobutyl ~ethacrylate, n-octyl methacrylate, dodccyl me~hacrylate, 2-ethYlhexyl ~ethacryl~te, st~aryl methacrylate, phenyl methacrylate, di~ethylaminoethyl methacrylate, diethylamino~thyl methacrylate, acrylonitrile. m~thacrylonitrile, acryloamide, glycidyl acrYlate, ~Iycidyl methacrylate, acrylic acid, meth~crYIic acid, 2-vinylpyridine or 4-vinylpyridine.
Among the above. howeve~, polystyrene or a styrcne-acrylate or methacrYlste such as butyl acrYIate or butyl methacrylate is prsferrcd.
The organic solvent us~d in the preparation of resin 12 22 36 ~06 532 7~63 MA~IN0 & COMPANY 1~11/0~7 ~Q22~

solution is such that the blnder resin used is soluble therein. It is preferred that the dye or Piement used is readily wetted with the solvent. Since any dye or pigment is ~enerally of high polarity, the solvent used preferably has a polar group therein. Th~refore, there may be mentioned as such pol~r sol~ants, for exa~Ple, aliphatic ketones such as methyl ethyl ketone or methyl 5sobutyl hetone. alkyl esters of lower aliphatie carboxylic acids such as m~thyl acetate. ethyl acetate, propyl acetate or butyl acetate, lower aliphatic ~Icohols such as propanol or butanol, or ethers such as tetrahydrofuran. However, when a dYe or a pigment of a relativHly low polarity is used, an aromatlc hydrocarbon 9uch ~s tolu~ne or xylene may be used as the solvent. When needed, a mixture of the ~llphatic alcohol and tha aromatic hydrocarbon may be us~d ac the sol~ent Ho~ver. the solvent ~sed in the invsntion is not limlted to the abova 0xe~pl~fied.
in the prgParation of ths resin sol~tion, ~ res5n is used in an amount of 1-40 parts by ~elght, preferably in An amount of 5-20 paFts by wel8ht, In relation to 100 parts by weight of the organ~c 8 0 I V ent.
The resin solution is prepsred by dissolvin~ a resin in an organic solvQnt as hcreinbefore set fortb. but the resin solution may b~ prepared by polymerizing a poly-~erizable monomer in an organic solvent. In ~he l~tter method, the resultant resin solution may contain unreacted monomers.
Then a dye or a pigment is added to the resin solution, and m~lled and disPersed therein bY use of a cunv~nliun~l mill;ng ~ns DUC a~ a h~ll mill. th*r~by to prePare a ~ixture of resin, dye or pigment. and solvent.
~hen desirable, a dispersing agent s~ch as ethylene-~inyl acetate coPolymers may be used in the preparation of l51~ mlxtule, ~hen 3u~h a disp~roine a~en~ io ussd. a ~elatively low polar org8nic ~olvent is prsferablY used as 22 37 2S~ 532 78~3 MAKINO ~ COMPANY ~012~047 2~22~

a medium for th~ mlxture. The dy~ or pigment functions as a coloring a~ent ~Ind/or a ch~rge control a8ent in the resul tant toner p~rticl~s.
The dy0 or pigment used ~n the ~nvenSion is not specifically lim;t~d, and there may be m0ntioned. for ex3mple~, a proton donatin~ dye stlch ag a ni~rosine dy repr~sen ted by:

~ U $

wher~in X~ is ~n anlotl ~pocl~, and a pro~on ~cc~ptin~
d~e sllch a-~ ~ chrolliu-i Gontslning dye r~pressnt~d by:

~ 1~ x ~R I N~NO~

wh4tH;n X~ i~ a cation species, or Spi~on Bl~ck TRH~ (by Hodogay~ N0gak~ Kogyo K. K., Japan) rePre~en tcd by:

' 9~8, . 19~2e~ ~6 532 7863 MAKINO & OMPANY ~ 2~002 2022nl~

0,N~O 1 ~CO~H~) ~IINOC~ T _~N 0 wherein ~1' is a c~tlon ~peci0~.
C~rbon bl~ck is pr~lfcrably use~ ~s a coloring agcnt in the production o~ ~onochro~atic toaer particl~s whereas a Y~riety of ~o dyes or phthalocyanino plgmsnts are preferably used ~n the productlon of colorcd toner particles.
The dye or pi~nlont 1~ u~d in 3n emount o~ 1-40 parts by weight, preferably in an amount of 2^50 parts by ~eight, in rel~tion to 100 part~ by wl~ht of the orgsnic solvent used for the production of re~ln solu~ion.
The or~anlc solvent ls then removed from the mixture by any conventional means such a~ h~atin~ or d~Yin~ under reduced Press~re or frozen drylne ther~by to provide a ~a3t~r b~tch of th~ invention. The ~aster batch moY be cru~hed or 1~1 Ied, when needed.
The resultant m~ator batch h~s a dye or a pi8ment diapersed therein as finely dlvided p~rtlcle~ of not more thsn about 5 ~n, and ~bout 1 ~ ~ In prefHrred embodiments, eve~ ~hen the dye or pig~ent co~tains pa~tlcles iarger in dia~eter than the preferr0d toner part~cles.
~ ~a3ter batch 13 ~ener~llg defined as a colo~ed materlal co0po~ad of a rs3in havin~ a colorant disPersed therein in a hi eh con~ent. Such a ~agt~r bstch h~s hith~rto ~5 been pro~uc~d by m~lting an~ kneading to8ether a mixture ' ~0 08/t~2 22 38 ~)~ 532 7863 MAI:IN0 & COMPANY 014/047 2~22$~

of a resin ~nd a coloring agent in the absence of a solvent, cooling ths resultant kneaded mass and then crushing ~r granulating the mass, as hereinbefore set forth. However, a resin is generally of ION polarity whereas many dyes or pi~me11ts are Or h16~ lv.i~y~ t ~h~ ~o~ mc~t;onod conventional methods fail to provide a master bateh in which dyes or pi8ments are ev0nly dispersed t~erein a~
finely dividsd particles. tn contrast to this prior art, a ~aster batch is produced according to the invention by dissolvin8 a resin in an organic solvent to prepare a resin solution, ~illing and dispersing a dye or a p;gment in the resln solution to prcpare a mlxturs, and thcn th~
solvent is removed from th0 ~ixture. Thus, the ~ f the inventi~n Provide~ a m~ster batch which n.nntains a dYe or a pig~ent evenly disPersed thsrein as finely divided particles.
In accordance ~ith the invention, there is providod a further method of producin~ a master batch for the production of toner partcles used in electrophoto~raphy, which comprlses:
(a) d;~ olv;~ b;ndol . ~q;n; n An ore~n;c solvent to prepare a resin solution;
~b) milling and dispersing a dYe or a pigment in an organic solvent to prepare a di~persion; and (c) mixin~ the reein ~ol~tioo and the dispersion to~ether ~o ~r~pale a mlxture, ~nd r~movin~ the solv~nt f rom the mix ture The resin solution is pr~pared in the same manner as he~einbcfore ~t forth. In thi.e sacond method of produoing a master batch, ~ disPersion of a dYe or pigment in an organic solvent is prePared. and then the dispers;on is admixed with the resin solution to prepare a mixture.
~he solvent used in the preparation of the dispersion of a dYe or a pi~ment is such that the dye or pigment used is readily wetted therewith. lt is preferred tha~ lh~

2~2g~
8~ 22 ~0 ~P~6 532 7863 MAKINO & ~OMPANY 1~015~047 ~olven~ i~ th<~ mc ~ tho ~olvont i r1 th~ r~;n ~ ior~.
However, the solvent uged for the prepar~tion of the P~rs~ ay bc diff~rent from thc solvont in th~ r~sin solution if the reSin Is soluble therein when the resin soIution and the d iepersion ar e mlxed tog eth t' r to prepare a mlxture.
~ dye or a pigmeat is milled with a eonventional crushln~ ~eans ~uch as a bal I mi 11 and dispersed in ~
solvent to preP~rc a dispsrsion. In the preparation of ~ d;spel~loQ, ~ dr~ o- pl6mcnt i~ uood in ~n amount ~f 1-40 part~ by wal8ht, pr~f~rably in an ~mount of ~-50 parts by wel~h~, in t~0lation to 100 parts by wiaht of the organic solvent used. ~hen desitable~ a dispersing agent such 3s ethyll~ne-vinyl acet~te copol~Hrs may be ussd in the preparation of the di~Per~lon. Wh~n such a dispersing agant is used, a relatively low Polar organic sol~ent i9 pt~eferably u3ed as a mediull for the disp~rslon.
~ the preparntlon of a m~xture ~f the resin solution nnd the dispersion, the dlspersion ~s mixed wi th the resln ~olutlon so th~t the resultan~ mastsr batch contains the dy~ or Plrmcne tn 1l r~qulr~a ~r prcdc~r~lnu~ IVU~
Then the ~olv~nt i!l reMoved from the mixture by any conven-tlonal m~ans as h~r~lnbefor~ Ment~oned thereby to provide a ~as t~r ba Lch of tho i nvon t i on . The ma~ tcr ba tch ~a~ be cru9h~d or mi I led. ~h~n n0sded.
Sim{lsrly ~ith the master b3tch prepared by th~
firqt ~ethod, th0 resultant ma3t~r ba kh prepared by the ~econd ~thod al~o h~s a dYe or a pigment dispersed therein as finely dlvid~d particles of not mor~ than about 5 ~ ~, and ~bout 1 ~ ~ in pr~ferred e~bodimen ts, even wh~n the dy- or P~e~ent cont~nq ~rticl~s larger in diareter than Ihs Prc~orred tonor particlo~.
A~ a ~urths~r 31~p~Ct of th~ ;Rv~n~ n, th~re ig provid~d a ~ethod of produclng toner partlclf~,s f<~r u~
c I ec tropho tography . The r~e thod, i n add I t i on t~ the s teps ' 9~ 0~()2 22 41 ~lf3 532 7S63 MAKIN0 & COMPANY [i~016/1347 ~022~1~

o~ ~a), (b) and (~ r tho preparati~n of ~ m~ster b~tch.
further comprises:
(d) add{ng a further amount of a second binder resin to the master batch togeSher hith an effectlve amount of an additive when neCeSSarY, to form a sscond mixture. and kneading the second mixture to a composition; and (e) crushing the composition to toner particles.
The second binder ~esin may be either the same as or different froM the first binder resin usod in the Production of the master batch. But when the second binder resin is different from the first, it is preferr~d that the sscond bind~r resin is comPatible wl th the first binder resin.
The additives used in the production of tonsr particles are ~ell known in the art of toner production, lS and are added in an effective amount to the master batch together with the second binder resin so that the resultant toner particles have desirable or designed proPerties. For instance, the additive ~ay be a magnetic material to provide toner partlcles with magnetic properties or a polyolefin wax such as polyethylene wax or poly-propylene wax to provide toner particles wlth antioffset prop~rties. A dye or a pigment such as hereinbefore mentioned may also b~ incorporated into toner particles as an additive in this sta~e. Magnetic oxides such as ferrite or magne~ite, or other magne$1c metals are used as the magnetic material~ The magnetic materi~l is used in an amount of 30-300 parts by weight, preferablY of 30-1~0 parts by weight, in relation to 100 parts by Nei~ht of the total amount of bindor resin used.
As a still further aspect of the invention. such a mastcr batch may be produced according to the inventlon as conSains a dye or a pigment or other additives in such an amount that toner particlcs require. Such a mas ter bs tch is crushcd and millsd as it is or after being mixed with additives to provide toner particl~s. The master batch in _ ~ g~l 0~03 2~):32 ~lB 532 7~ff3 MAKINO & COMPANY 1~ J1 2 ~

this sense does not contain a dye or a pi~en~ in A high content, but it is referred to as a master batch in the invention.
The above master batch may be produced by either method set forth hereinbefore. ~ors specificallY. a dYc or pigment is added to and ~ixed with a solution of resin, the dYe or pigment is milled and dispersed in the solution. and then the solvsnt is removed fro~ the mixture to provide a magter batch. Alternatively, ~ dispe~sion of ~ye or PigmenS is added to and mixed with a solution of resin to dlsperse the dye or pigment in the solution. and then the solvent ls reMoved from the mixtu~e to provide a master batch. In these methods, however, a dYe or pigment is u6ed in an amount of 0.5-10 parts by weight. preferably 1-5 parts by weight in relation to IOO parts by weight of rssin.
When the toner of the 1nv~ntion is used as a two-component developing aeent, the toner is ~ixed with a carrier material such as a powder of iron. ferrite or ~0 ~a8netite aj well known in the art of el~ctroPhotograPhy, The two-component developing agent contains th~ toner in an amount of 2-20 X by weight, preferably of 5-10X by weight.
~ he resultant toner particle~ have a uniform dis~ri-bution of ~pecific electric charge snd coloring agen~ so that they produces eithar ~onochromatic or full color Loner images with a sufficient darkness constantlY free from fogs or contamination thereon. Further, there arises no prblem of fil0in~ of toners on a photoconducti~e body.
The invention will now be described more specifically with reference to examples, howev~r, the lnYention is not limited thereto.

xa~Qle One part by weight of a nlgrosina dye ~Nigrosine Base EX available fro~ Orient Kagaku Xo~yo X.~ s a charge ~o 08~l~3 20l~ ~l)6 532 7~3 MAKINo & c`Ol~PANY ~3/~J32 2022~

controlJing agent and 0.4 parts by wei~h~ of ethylene-vinyl Acetste copolymer (Soablene CH dva;lable f~om Nippon Goaei Kagaku Ko~yo K.K.) as a dlspersing ~gent were addad to 10 parts by ~eight of xylene. The mixture was milled in a ball mill over a p~rlod of 50 hours lo provide a disp~rsion of dyo.
An amount of 80 pa~ts by weight of stYrsne and 20 parts by w~ight of b~tyl methacrylate were copoly~eri2ed in xYlene using azobisisobutYronitrile as a polYmsrization initiator to prep~re a solution of low molecular weight styrenlc copolym~r h~ving a wei~ht averaee molecular weight of 2.0 x 10~1 a glass tran~itlon teMperature of 72 C and an acid v~lue of 0.1.
An amount of 60 parts by weight of styrene ~nd 40 psrts by wslght of butyl methacrylate w~e bulk-copolymeriæ~d and then solution-copolYmerized in xylene to prepare a solution of high ~ol~cular weight styrenic copolymer havln~ 8 weight avers~e molecular weight of 3.0 x 10~. a ~la~s transition temperature of 60-C and an acid ~0 valus of 0.1.
th~ solution of low molecular wei~ht st~renic copolyer and the solution of high molecular weight slyrenic copolymer wore mixed toRether ln ~n squdl weight ratio. Ths above ~entioned dlsperslon o~ charge controlling agsnt was addsd to the resln solution dnd the mixture was stirred. The mixturs was thsn heated undar reduced pressure to remove the solvent therefrom and the resul~ant ~ass was cnushed to provids a master batch.
An amount of 101 par~s bY weight of the master batch (compos~d of 100 psrt~ by weight of binder rssin and one part by weight of charRe controllin~ ~ent) was mixed with thrse parts by we~ght of low molecular weight polypropylene (ava;lable from SanYo Kas~i Kogyo K.K.) 1.5 parts by weight of carbon black (MA-8 av~ilable from Mitsubishi Kasei KogYo K K.) and 60 pa~ts by weight of magnetite powder 3 2~) 07 ~36 532 7~63 MAK I NO & COMPANY 1~ 004~032 20~2~

~EPT S0 available from Toda KoeyQ K.~.). melt-kneaded ~iSh a twin screw extruder, and then milled with a ~e~ mill, The resultant powder was classified to provide toner particl~s of 5-20 microns, The toner was aPPlied to a commercial copying machine (Model NP-150 available from Canon K,U,) and lO000 sheets of copi~s were made continuously to evaluate copied images.
The results are shown in the Table l, while the relation between the number of sheets coPied and the i~age darknes~
i9 shown ln Fig, 1. All of the images were clear and had no background contaMination. No fil0ing was observed on the photoconductor, The toner was mixed with a carrisr Material in a concentratlon of 5 X by weight to prepare a developer and tha distribution of triboeleotriclty of the toner was measured by use of a charge distribution testing mschine (available from Hosokawa Micron K,K.), As the results are shown in Pig. 4, the toner was found to have a narrv~
distribution of triboelectricity.
~0 ExamPle 2 Three p~rts by weight of the nigrosine dye and 1.2 parts by wHight of ~hs ethylene-vinyl acatate copolymsr, both th~ same as used in the Example 1, were added to 30 parts by weight of xYlene. The mixture was mil1ed in 8 ball mill over a Period of 50 houra ~o provide a dlspersion of charge con~rolling agent, The solution of low molecular wRight stYreniC
copoly~er and the solution of high molccular ~oight styrenic copolymer, both the same as in the ExamPle 1. were mixed to~ether in an eqùal weight ratio. The a~ove mentjoned dispersion of char~e controlling agent was added to the rosultant solution, and the mixture was stirr~d. The mixture was then heated ~nder reduced pressure to remove the solven~ therefrom, and the resultant ~ass was crushed ~ ~o l)8~3 20 07 ~ 532 7863 MAKINO ~ OMPANY 12 0~5/~332 2~22~11 to provide a master bstch.
An amoun~ of 103 parts by weight of the master batch (comPosed of 1~ parts bY wei8ht of binder resin and three parts by height of chargs controlling agent~ was mixed with three parts by weight of the low molecular weight poly-propylene, 1.5 parts by weight of carbon black lnd 60 parts by weight of magnetite powder, all the same as in the Exa~ple 1. melt-knead~d with a twin screw extruder. and then milled with a jet mill. The resultant powder was classified to provide toner particles of 5-20 microns.
In the same manner as in the Example 1, 10000 sheets of copies were Made continuously to evaluaSe copied ima~es.
The results are shown in the Tabla 1, wbile Fig. 1 shows the relation betws~n the number of copied sheeta and the i~age darkness, All of the sheets were found to have clear imags~ without background contamination. No filming was observed on the photoconductor.
~ he tonar was mixed with 8 c~rrier material in a concentration of 5 X by wsight to prepa~s a developer and the distributlon of triboelectricity of the toner was measured in thH sa~e manner as in the Exa~Ple 1. As the rssults are shown In Flg. 4, the ton~r was found to have a narrow distribution of tribo~lectricity, Thrse parts by wei~ht of the nigrosin~ dye and 1.2 parSs by weight of the ethYIene-vinyl acetate copolYmer, both the same as used in the Example 1, were added to 30 parts by weight of xylen~. The mixlure was milled in a ball mill over a period of 50 hours to provide a disPersion of charge controlllng a~ent.
The solution of low molecular we}sht stYrenic copolymer and the solution of high molscular weight styrenic coPolymer, both the same as in the Example 1, were mixed together in an equal weight ratlo. The above mentioned ` ~0 ~8~3 2~1 08 ~l:)6 532 7~3 MAI~IN0 & COMPANY ~006/~)32 2Q22~1 1 dispersion of charge controlling 3gent was added to the resultant solution in such an amount that the resultant mixture contained one Part of charge controllin8 agent i n relation to 10 parts by wei~ht of solid resin, and the mixture was stirred. The mixture was then heat~d under reduced pressure to remove the solvent therefrom. snd the resultant ~ass was crushed to provide a master batch.
An amount of 11 parts by weight of the master batch (composed of 10 p~rts by weight of binder resin and one part by weight of charge controlling agent) was mixed with 90 parts b~ weight of styrene-butyl methacrylate copolymer (a mixture of the aforesaid low molecular weight styrenic copolymer and high molecular weight styrenic coPolYmer in an equal weight ratio), 3 psrts by ~eight of the loh molecular weight polypropylene, 1.5 psrts by welght of carbon black and 60 parts by weight of magnetite powder, all the sa~e as in the ~xample 1. melt-kneaded with a twin screw extruder, and then milled with a 3~t m~ll. The resultant powder was clsssified to provide toner particles Of 5-20 microns, In the same ~anner as in the Example 1, 10000 sheets of copies were made continuo~sly to evaluate copied 3mages, The results are shown in the ~able 1. while Fi~. 1 shows the rulati~n betw~n th~ numh~r nf copied sheets and the image darkness. All of the sheets uer~ found to have cle~r ima~es w}thout background contamination. No filming was observ~d on the photoconductor.
The toner w&s mixed with a carrler mat~rlal in a concentration of 5 X by wei~ht to prepare a develoPer ~nd the distribution of triboelectrlcity of ~he toner wa3 Measursd in the same ~anner a~ in the ExamPle 1~ As the results are shown in Ple. 41 the toner was found to have a narrow distribution of triboelectricity.

ExamPle 4 sO(8~03 20~1g ~l~6 532 7863 MA~INO & COMPANY ~)7/~32 21D22~

Three pa~ts by weight of monoazo chromium dye Spiron Black ~RH from Hodo~aya Ka8aku Kogyo K K.) as a char~e contro]ling a~ent and 1.2 parts by wei~ht of the same athylene-vinyl acetats copolymer as in the Example 1 were added to 30 parts by weight of xylene, The MiXtUre was milled in a ball mill over a period of 50 hours to provide a dispersion of char8e controlling agent~
The solution of low molecular ~eight styrenic copolymer and the solution of high ~olecular wei8ht styrenic copolYmer, both the sa~e as in the example 1, were mixed together in an equ~l wsight ratio. ~he above ~entioned dispersion of charge con~rolling agent was added to the ~sin solution, and the mixture was st~rred. The ~ixt~re was then heated under reduced pressure to rem~ve the solvent therefrom, and the r~sultant mass was cr~shed to provide a maste~ batch.
An amount of 103 parts by weight of ~he maste~ batch ~co~pos~d of 100 parts by weight of binder resin and three parts by weight of charge controlling agent) was mixed with three Parts by ~eight of ths low molecular weight poly-propylene and 10 p8rts by weight of carbon black, melt-k~eaded with a twln screw extruder, and then milled ~ith a jet mill. The resultant powder was classified to proYide ton~r particles of S-20 ~icrons.
In the saMe ~anner as in the 8xamPIe 1. lQ000 sheets of copies w8re made cont~nuously to evaludte coPied images.
The results are shown in the Table 1. while Fi~. 3 shows the relation between the number of copied sheets and the image darkness. All of the sh~ets wero found to have clear images ~ithout background contaminatlon. No fil~ing was obs~rved on the photoconductor.
The toncr wao mixsd with a carrier m~terial in d concent~ation of 5 X by weight to Prepare a devsloper and ths distributian o~ triboelectricity of the toner W3S
m~asured in the same ~anner a~ in the E~a~Ple 1. As the ` ~0 t~83 2() 1~) ~()6 532 7863 MAKIN0 & COMPANY 1~ o8~32 2~22~1 results are shown in Fig. 6. the toner was found to have a narrow distribution of trlboelectricitY.

Comparative Exam~le One part by weight of the same nigrosine dye as in the Example 1. 100 parts by weight of the same styrene-butyl methacrylate copolymer as prepared in ths Exam~le 3, 3 parts by weight of low molecular weight polypropYlene, l.S part~ by weight of carbon black and 60 p~rts by wei8ht of magnetite powder, all the sa~e as in the Example 1.
were mixed together, The ~ixture was th~n melt-kneaded with a twin screw extrudar. and then ~illed with a jet mill. The resultent powder was classif{ed to provide toner particles of 5-20 mi~ronS.
In the sam8 manner as in tho ~xample 1. 10000 sheet of copiz~ werc made continuously to evaluate eoPiHd i~ages.
~he results are sho~n in th~ Tabl0 1I while Fig. 2 showa the relation betwe~n the nu~b~r of copied shests and the image darkness. A~ound tbe 1sst stage of 10000 sheets copying, the Ims~es were found to be remarkablY contaminated and unclear, The tonsr was mixed wlth ~ carrier Material in a concentration of 5 X by wei~ht to prepare a develoPer and the distribution of triboelectrici ty of the toner was measured In th0 same manne~ as in tbe ~xample 1. ~s the results ars shown in Fig. 5, the tonsr was found to have a wide distribution of triboelactricity, ComPa ra tive E~ample ~
Three parts by weieht of nigrosine dye were used.
but otherwise in the sams ~anner as in the Co~Parative Example 1, toner particles were prepa~ed.
In the sa~e manner a~ in the ~xample 1, 10000 sheet of copies were made continuously to evaluate eopied i~a~es.
~he resultq are shown in the Table 1, while Fig. ~ shows ~ 9~ 3 2~ 6 532 78~3 MAKINO & COMPANY 1~0~/~32 2~22~

the relation between the number of copied sheets and the i~age darkness. Around the last stage of 10000 shee~
copyJn~, the ima~e~ got remarkably contaminated and uncle~r. Filiming was observed on the Photocanductor.
The toner was mixed with a carrier material in a concentration of 5 X ~Y ~eight to prepare a developer and the distribution of ~riboelectricity of the toner ~as measured in the same mann~r as in the Example 1. As the results are shown in ~ig. 5, the toner was found to have a wide distribution of triboelectricity.
Çomparativ QExamp~e 3 A developer wa~ pr~pa~ed bY ~ixing 100 parts bY
weight of toner particles prepared in the Co~Parative Exa~ple ~ with one part bY weight of cerium oxide.
~n the SaM8 mdnner as in the ExamPle 1. 10000 sheet of copies were made continuouslY to evaluate copied images.
Th~ results are shown in the Table 1, while ~ig. 2 shows th~ relation betw~en the nu~ber of copied sh~ets and the iMage darkne~s, The toner failed to prov~de copies having a stable ~msge darknesses.
The toner was mix~d with a carrier ~atarisl in a concentration of S X by weight to prepare a dsveloper and the distribution of t~iboslectricity of th~ toner was measursd In the sama manner as in the Example 1. As the results are shown in Fig. 5, the toner was fo~nd to have a wide distrlbution of triboelectricity.

ComP~rative Exa~Ple 4 3~ One part bY wei~ht of monoazo chro~iu~ dye (SPiron Black TRH), 100 parts by weight of styrene-acrYlic acid copolymsr ~Himer TB-1000 available from Sanyo Kasel Kogyo K.K.), 3 parts by w~ght of low molecular weight poly-propylene and 10 parts by weight of carbon hlack, ~o~h the 35 same as in the examPle 1. wera mixed together. ~he mixture '9~) 08~)3 20 12 ~ 532 7863 MAKINO & (.OMPANY ~ J/~32 2 ~

was melt-kneaded ~ith a twin screw extrudèr, and then milled with a jet mill. The resultant powder was classified to provide toner particles of 5-20 mlcrons, ~n amount of 0.3 parts by weieht of silica powder (Aerosil R-972 available from Nippon Aerosil K.K.) was added to and ~ixed with 100 parts by weight of toner particles. A developer was then prepared b~ Mixing the toner particlas with iron powder (E~V-2S0 available from Nippon T~ppun K,K,) in a concentration of 6 % by weight, The developer was aPPlied to a commercial copying machin~ (SF~-1102-Z available from SanYo Denki K.K.~ and 10000 sheets of copies ~ere made continuouslY to evaluate copied images, The results are shown in the Table 1, while Fig. 3 shows the relation bet~een the number of copied sheeta and the imaBe darkness. Around ths l~st stage of 1~00~ sheet copying. there was observed remarksble fo~ on the ima~es. Also no copies ~ere obtained with a stable image darkness, The toner was mixed ~ith a c~rrier material in a conc~ntration of 5 X by welght to prepars & dsvoloP~r and the distribution of triboelect~icity of the toner was measur~d in the same manner a~ ~n the BxamPle 1. As the results are shown in Fig. 6. the toner was found to have a wide distribution of triboelectricity.

' 9O e~ .0 13 2S~16 532 7863 MAKINO ~ COMPANY ~1011~032 2Q22~

TABLE
... . . .
lmage Fog on ~ min~ Reproduc-~rkn~ss Image on Photo- tivity of ~ ---- conductor Fine lnltiAl Finsl~ Writin s ~XamPIe 1 1.22 1.~3 NO NO E%Ce1lent 2 1 . 25 1 . 27 NO ~IO EXCe I I en t 3 1.?3 _1.23 _NO IIO EXCellenl CrfiPara t i Ve 10EXa~PIe ~ 6 1.02 YeS NO ~ad 2 1.22 1.~8 YeOE Yes Excellsnt _ 3 1.23 I.17_ YeJ No Excellent ExsmPle 4 1.4~ 1.38 No No Excellent C o ~ e 15E~PI~ 4 1.33 _ 1.43 Y~S No Excellcnt ~) Around IOOOOth lheet of copy Ex~m~lo 5 An amount of ~.5 P~rts by weight of monoa~o chromium dy~ (Spiron Black TR~ avallable tro~ Nodogaya Ka~aku Kogyo K.K.) a~ a char~e controlling ~gent and 0.2 parts by weight o~ ethyl~ne-vinyl acetats coPolymer (Soablene CH available from Nlppon Gos~i Kagaku Kogyo K.K.) a3 a di~Persing agent were added to 5 parts by ~Bht of toluene. The mixSure was millRd in a ~all ~11 over a poriod of 50 hours to prepare a di~pergion of char3e controllin~ agent.
One p~rt by welght of styrene-acryllc acld ester coPoly~er tHi~er TB~1~00 available fro~ SanYo Kasei ~o8Yo K,K.) as ~ binder resin w~s dissolved in 10 parts by weight of toluene to PrePare a rcsin solut;on.
The ~bov~ mentioned disper~ion was added to the resin solution, and the ~ixture was stirred, ~he mixture was then heated under reduccd pressure to re~ove the solvent thore-from, and th6 re~ultant mass ~ crashed to provide a ~aster 3~ batch.

~ 90 O~ 3 2~)~13 ~6 532 7.~63 MAKINO & COMPANY 1~l0l2~03~
2~22~ 1 An a~ount of 1.7 parts by weight of the ~aster batch, 98.8 parts by weight of the same styrene-acrylic acid ester copolym~r as above. three parts by weight of low molecular wei~ht Polypropylene (Biscol 550-P avai lable from Sanyo Kasel Kogyo K,K,) as an antioffset a~ent and 10 parLs by wRight of carbon black (MA-8 avai lable from ~li tsubishi Kasei Kogyo K.K,) wcrc mlxed and mel t-kncsded wi th a twin screw extruder, and then mllled with a ;et mill. The resul tant powder was classif ied to provide toner Particles of 5-~0 raicrons, ~n amount of 0,3 parts by weight of si 1 ica powder (Aerosil R-972 avallabla fro~ Nippon Aerosii K.~.) w~s added to 100 parts by weight of toner particles. and then tha ~i x tur0 wa~ f urthcr ;ni xed wi th a carr i er ma ter i a I
lS (iron powder EFY-250 availabla fro~ Nippon ~eppun K.K.) in a concentlAtion of 6 % by weight, thereby to pr~Pare a two-co~ponen t deve I oper.
The developer was applied to a com~ercial copYin~
machine (SFT-1102-Z available from Sanyo Denki K.K,) and 10000 sheets o~ cop~as were made continuously to evaluate copied imagos. As the re~ul ts are shown in the Table 2.
images were cl~ar and had no background contamination at the last stage of 10000 shee~ copying. Further. as the ralstion between the number of sheets of coPies and their 2S image darkness Is shown in ~ig. 7, the d8rkness was ~ubstantially constant over continuous copying operation.
~o fil~ing was obse~ved on the photoconductor.
The toner was ~ixed ~ith a Garrier material in a concentration of 5 X by weight to prepare a developer and the distrlbution of triboelectricity of the toner was ~easured by use of chag~ distribu t i on tes t i ng machine tavailabla from Hosoka~a Mlcron K.K.), As the results arc shown in Pl~. 9, th~ ton~r was f~und to have a narrow distributlon of triboelectricitY, and contain sub~t~ntially no particlcs reYerslbly charged.

` g~) ~8~03 2(1 1~ ~6 532 78G3 MAKINO & OMPANY 1~013~32 2~22~11 ExamPle 6 One part bY weight of dye and 0.4 Parts by weight of 8thYlen~-vlnyl scetate copolymer, both the same a~ in the Example 5, were added to 10 Par~s by weight of toluene.
Jhe mixture was mill8d In a bnll mill over a Period of 50 hours to prep~re a dispersion of charge controlling a~ent.
Two parta by welght of the same styrene-acrYlic acid ester copolymer as i n the Example 5 were d;ssolved in 20 part.~ by weight o~ toluene to prepare a resin solution.
~ he above mentioned dispersion was added to the resin solution, and the mixture was stirred. The ~ixture was then h0ated under reduced pressure to remove the sol~ent there-f~om, and the resultant ~ass was crushed to provide a msster batch, An amount of 3.~ parts bY weight of the master batch, 97.6 part9 bY weight of the same styrene-acrylic acid e~ter copolymer as above, thr~e P~rts by weight of low moleculsr welght polypropylene and 10 parts b~ ~esght of carbon black, all the sa~e aa before, were mixed and melt-kneaded with a twin scrëw extruder. and then milled with a jet mill. The resultant powder WAS classified to provide toner particles of 5-20 microns.
An amount of 0.3 parts by wei~ht of silica powder ~Aerosil R-972 available from ~ippon Aerosil K,K.) was added to 100 parts by weight of tone~ particles. and then the ~Ixture was further mlxed wlth a carrier material ~iron powder ~FV-250 available from ~iPpon Teppun K,K.) in a con~entration of 6 % by wei~ht, thereby t~ prepare a two-component develoPer.
In the same manner as in the Example 5. 100~0 sheet of copieg were made continuouslY to evaluate copied images.
The results are shown in the Table 2, while Fig, 7 shows the rela~ion between the number of copied sheets and the ima8e dsrkness. Thcre were obtained clear ;ma~es without .

18~03 2~15 ~O~ 632 78~3 MAKINO & ~:~OMPANY 1;~01~1~()32 2022!~1~

back~round con~amination at th~ last stage of 10000 sheet copying. Nei~her filming on ~he photoconductor nor conta~ination in.qide the copying machina with toner particles werf observed.
The toner was mlxed with a carrier materlal in a concentration of 5 % bY weight to prepare a develope~ ~nd the distribution of triboelect~lcity of the toner was measured in the same manner as in the ExarPIe 1. As the results are shown in Fi8. 9. the toner was found to have a narrow dlstribution of triboelectricity, and contain Qubstantially no particles reversibly charged.
e xam D le _7 One pArt by wgi~ht of nigrosine dye (Nigrosine Base EX available ~rom Drient Na~aku Kogyo K.K.) as a charge controlllng a~ent and 0.4 parts by wsight of the same ethylene-vinyl acetate copoly~er as in the ExaMple 5 were added to 10 parts by wei8ht of toluene. The mixture was milled in a ball ~ill over a period of 50 hours to prepare a di9perslon of char~e controlling a~ent.
~wo parts by welght of the same stYrene-acrYlic acid e~ter copoly~er ~a in the Example 5 were dissolved in 20 parts by weight of toluene to prepars a ~esin ~olution.
The above nlention~d dispersion was added to the r~sin 25 solution, and the ~Ixture w~s stirred The mixture was then heatcd under r~duced pressure to rcmove the solvent there-from, and the resultant mass was crushed to provide a master batch, An amount of 3 4 parts by weight of the master batch, 97.6 parts bY weight of the sam~ styren~-acrylic acid ester copolymer a9 above, thr~s p~rts by height of low molecular welght polypropylene and 60 parts by wei~ht of magnetite powder (~PT-SOO available from Toda KogYo K.K.) were mixsd and ~elt-kneaded with a twin screw extruder, and then millsd with a iet ~ill . ~he resultant POwder was classiflad to ' 90 0~03 2l~ 18 ~013 532 '78~33 MA~INO & COMPANY 1~315~03~
2Q~2~ ~

provide toner particles of 5-20 microns.
In the same manner as in the Example 5. 10000 sheet of copies were made continuouslY to evaluate copied images, The results are shown in the Table 2, ~hile Fig. 11 shows the relaSion between the number of copied sheets and the image darkness. There wer0 obtained clear images without background contamination at the last sSage of 10000 sheet copying. Neither filming on the photoconductor nor contamination inside the copying machine with tone~
particles were observed.
The toner was mixed with a carrier material in ~
concentration of 5 X by weight to prepare a devaloper and the distribution of triboelectricity of th~ toner was measured in the sam6 Manner as in thc Example 1. As the results are shown in Pi8, 13, the toner was found to have a narrow distribution of triboelectricity, and contain substantially no particles reverslbly charged.

ExamPle ~
Three Parts by weight of the sa~e nigrosine dye as in the Exampls 7 and 1.2 parts by weight of the ~ame ethylene-vinyl acet~te copolymer as in the Example 5 ~ere added to 30 parts bY welght of toluene. The mixture was milled in a ball mill over ~ perlod o~ 50 hours to prepare a dispersion of charge controllln8 agent.
Six parts by ~eight of the sa~e styrene-acrYlic acid ester copolymer as in the ExamplH 5 were dissolved in ~0 parts by weight of toluene to prepare a resin solution~
The above mentioned dlspersion was add~d to the resin solution, and the mixture was stirred. ~he mixtu~e was then heatsd under ~educed pressure to remove the solvent there-from, and the resultant mas~ w~s crushed to ~rovide a maste~
batch.
An amount of 10.2 parts by weight of the master batch.
92.8 parts bY weight of the same styrene-acryl~c acid ester )3 ~ 17 ~ 532 7863 MAKINO & COMPANY Ç~016/~32 2~22Q~

~8 copolymer as above, three parts by weight of low molecular weight polypropylen~, 1.5 parts by weight of carbon black and 60 parts by weight of ~agnetlts powder, all the same as before, were mixed and melt-kneaded with a twin screw extrudor, Rnd then milled with a iet miil. The resultant powder wa~ classi~isd to provid~ toner particles of 5-20 mlcrons, In the same manner as in the Example S, 10000 sheet of copies were madc contlnuously to evalu~te copied images The r0sults are shown in the Table 2. while Fig. 11 shows the relation bstween the number of copied sheets and the image darknHss. There w~re obtalned clear images without background contamination ht the last stage of 10000 sheet copying. Nelther filming on the photocond~ctor nor lS contamination Inslds the copying ~achine with tonsr particles were obsHrved.
the toner was mix~d with a carrisr material in a concentration ~f 5 X by weight to prePare a dev~loPsr and the diatribution of triboelectricity of ths toner wa9 ~easured in the ~s~e ~anner as in the Example 1. As the results are shown in Pig. 13, the toner was found to h~ve a narrow distribution of triboel8ctricity, and contaln substantially no particles reveraiblY chsrged.

Co~Parative exa~ole 5 An a~ount of 0.5 parts by weight of ~onoazo chromium dye, 100 p2rt~ by weight of ethylene-vinyl acetate copolymer, 3 parts by welght of low molecular weight polypropylene and 10 parts by weight of c~rbon black were mixed and melt-3~ kneaded w~th a twin screw extruder, and then milled withJet ~ill. The resultant p~wder was classified to provide toner particles of S^20 micron~.
An a~ount of 0.3 parts by weight of silica powder (Aerosil ~-972 available from Nippon Aerosil K.K.) wa~
added to 100 parts by w8ight of toner p~rticles. and then ~ g~ o~ 3 2tl 1~ 532 7~3 MAKIN0 & COMPANY [~17~032 2~%~Qll the mixture WdS further ~ixed with a carrier mat~ri~l ~iron powder ~FV-250 available from Nippon Teppun K.~,) in a concentration of 6 X by weight, thereby to prepare a thO ' co~ponent developer.
In the s3~e manner as in the Exa~Ple 5. 1000~ sheets of copies were made continuouslY to evaluate copied images.
~he results are shown in the ~able 2, while Fig. 8 shows the relation between the number of copied sheets and the image darkness, The developer Provided toner images having varicd i~age darkness and fog.
The tonsr was mixed with ~ carrier material in a concentration of 5 X by we1ght to prepare a develoPer and the distribution of tribocle~tricity of the toner was measured in the ~a~e ~s~er as i n the ExamPle 1. As the results are shown in ~ig. 10. the toner was found to have a wide distributlon of triboelectricity, and contain a significant amount of rever~ibly charged particles.

One part by weight of ~onoazo chro~iu~ dye was used, and otherwise in the sam~ ~anner as in the CoMparative Exa~Ple S, a develoPcr was prepar~d.
In the sa~e ~anner as in the Example 5, 10000 sheets of copies were Mad~ contlnuously to evaluate copied images.
The results are shown In the Table 2. while Fig, 8 shows the relation b~tween the number of copled sheets and the i~age darkness, The developer provided toner iMages having varied image darkness and fog, The toner was m~xed with a carrier material in a concentration of 5 X by weight to prepars a develoPer and the distribution of trlboelectriclty of the toner was ~easured in the sam~ ~anner ~s in the ExamPle 1. ~s the results are shown in ~Ig. 10, th~ toner was found to have a wide distributlon of trlboelectricity, and contain a significant a~eunt of ~eversibly char~ed particles.

` 90 08~03 20 19 ~1~6 532 7~63 MAKIN0 & COMPANY 12101~/kl3~
2~22~ ~

Com~a,r~tive examole 7 T~o parts by weight of monoazo chromium dYe was used, and otherwise ~n the same manner as in the Comparative S Ex~mple S. a developer was prepared.
In the sa~e manner as in the Example 5. 10000 sheet~
of coples here made continuously to evaluate copied images.
The results sre shown in the Table 2. while Fig. 8 shows the relation bet~cen ths number of copied shee~s and the image darkness, The developer Provided toner images having varied image darkness and fog.
The toncr was mixed with a carri~r msterial in a concentration of S X by weight to prepare a developer and the distribution of triboelectricity of the toner was measured in the sams manner as in the Example 1. As the result~ are shown in Fig. 10, the toner was found to have a wide distribution of triboelectricity, and contain a 3ignificant smount of reversibly char~ed Particles.

~
One p~rt by weight of the ~ame nigrosine dY~ as in the 8xaMple 7, 100 p2rts by weight of ethYlene-vinYl acetate copolYm0r, 3 parts bY wei~ht of low molecular welght poly-propylene, 1.5 p~rts by wei8ht of carbon black and 60 p~rts by weighht of magnetite powd0r, all the same as before, were mlxed and melt-kneaded with fl twin screw extruder, and then mill0d with a jot mill, The resultant powder was classified to provide toner partlcles of 5-20 microns.
In the sama ~nner as in the Exa~Ple S. 10000 sheets of copies w~re made continuou31Y to.evaluatP, copied ~mages, The results are shown in the Table 2, while Fig. 12 shows thc relation between the number of copied shee~s and the im~8e darkness, Iho develoPer provided toner ;ma~es havi~g varied i~a~e darkness and fog, The toner was mlxed wlth a carrier ma~erlal in a ' 90 ~18~3 2~) 19 t5`~1~ 532 78G3 MAKINO & COMPANY 1~lol~l/o32 concentration of 5 X by wei~ht to prepare a developer and the distribution of tribo~lectricity oF the toner was mea3ured ln ths same manner a~ in the ExamPIe 1. As th~
results are shown in ~ig. 14. the toner was fo~nd to havs a wide distribution of triboelectricity, and contain a 9ignificant amount of r~versibly chang~d particles~

ComDarative examPle ~
Throe parts by weight of ni~rosine dye w~s used and otherwise in the s~mc manner as in the ComParative Example 8, a developer was pr~Pared.
In the sa~e ~anner as in the Example 5, 10000 sheets of coPies were made continuously to evaluate copi~d images, The results are shown in the ~able 2. while Fig. 12 shows the relatlon between thH number of copied sheets and the image darknes~, Thc developer provided toner images havin~
varied imags darknes-~ and fog.
The tonor was ~ixed with a carrier material in a conce~tration of 5 X bY wei8ht to prepare a devoloper and th¢ distribution of triboelectricity of the toner was mea9ursd in the same manner as in the ExamPle 1. ~s the results are shown ~n P~8~ 14. the toner was found to have a wide distrlb~tion of trlboeleotricity, and contain a signiflcant amount of reversibly charged particles.

go ~ 8~ll3 2t) 2l~~06 532 7863 MA~ I No & ( OMPANY ~1 ()20/~32 2~22~

TABI,E 2 _ _ Image Fog on Piliming Reproduc-Darkne-cs Irnage on Photo- tivi ty of conduc tor Pi ne _ Inltial Final~ w~e~
Exa~p 1 e 11. 43 1. 39 No No Excs 1 1 en t 21. 37 1. 33 No No Exce I I en t . _ .................... ... ..
Compara t i ve Example 1 1.38 1.49 Yes No ~ad 2 1. 33 1. 43 Yes No Bad Exar~ple 3 1.24 1.2~1 No No 2xc~ nt Exa~pls 4 1.2~ 1.28 No No Excellent .. ._ __ .. . ... _ 15 Co~para t i V8 EXaMPIe 4 1. 16 1. 02 Yes No Bad Example 5 1.22 1.18 Yes Yfls Bad *) Around 10000th sheet of copY

Claims (15)

1. A method of producing a master batch for the production of toner particles used in electrophotography, which comprises:
(a) preparing a resin solution;
(b) preparing a mixture which has a dye or a pigment finely dispersed in the resin solution; and (c) removing the solvent from the mixture.

2. The method as claimed in claim 1 wherein the mixture is prepared by milling a dye or a pigment in the resin solution.

3. The Method as claimed In claim 1 wherein the mixture is prepared by adding a dispersion of a dye or a pigment in an organic solvent to and mixing with the resin solution.

4. A method of producing a master batch for the production of toner particles used in electrophotography, which comprises:
(a) dissolving a binder resin in an organic solvent to prepare a resin solution;
(b) milling and dispersing a dye or a pigment In the resin solution to prepare a mixture; and (c) removing the solvent from the mixture.

5. The method as claimed in claim 4 wherein the master batch contains the dye or pigment in an amount of 1-40 parts by weight in relation to 100 parts by weight of resin.

6. A method of producing toner particles for use in electrophotography, which comprises:
(a) dissolving a binder resin in an organic solvent to prepare a resin solution.
(b) milling and dispersing a dye or a pigment in the resin solution to prepare a mixture;
(c) removing the solvent from the mixture, therby to provide a master batch;
(d) adding a further amount of a second binder resin to the master batch together with an effective amount of an additive when necessary, to form a second mixture, and kneading the second mixture to a composition; and (e) crushing the composition to toner particles.

7. The Method as claimed in claim 6 wherein the master batch contains the dye or pigment in an amount of 1-40 parts by weight in relation to 100 parts by weight of resin,

8. A method of producing a master batch for the production of toner particles used in electrophotography, which comprises:
(a) dissolving a binder resin in an organic solvent to prepare a resin solution;
(b) milling and dispersing a dye or a pigment in an organic solvent to prepare a dispersion; and (c) mixing the resin solution and the dispersion together to prepare a mixture, and removing the solvent from the mixture.

9. The method as claimed in claim 8 wherein the master batch contains the dye or pigment in an amount of 1-40 parts by weight in relation to 100 parts by weight of resin.

10. A method of producing toner particles for use in electrophotography, which comprises:
(a) dissolving a binder resin in an organic solvent to prepare a resin solution;
(b) milling and dispersing a dye or a pigment in an organic solvent to prepare a dispersion;
(c) mixing the resin solution and the dispersion together to prepare a mixture, and removing the solvent from the mixture, thereby to prepare a master batch;
(d) adding a further amount of a second binder resin to the master batch together with an effective amount of an additive when necessary, to form a second mixture, and kneading the second mixture to a composition; and (e) crushing the composition to toner particles.

11. The method as claimed in claim 10 wherein the master batch contains the dye or pigment in an amount of 1-40 parts by weight in relation to 100 parts by weight of resin.

12. A method of producing toner particles for use in electrophotography, which comprises:
(a) dissolving a binder resin in an organic solvent to prepare a resin solution;
(b) milling and dispersing a dye or a pigment in the resin solution to prepare a mixture;
(c) removing the solvent from the mixture, therby to provide a master batch;
(d) adding an additive to the master batch to form a second mixture, and kneading the second mixture to a compo-sition; and (e) crushing the composition to toner particles.

13. The method as claimed in claim 12 wherein the master batch contains the dye or pigment in an amount of 0.5-10 parts by weight in relation to 100 parts by weight of resin.

14. A method of producing toner particles for use in electrophotography, which comprises:
(a) dissolving a binder resin in an organic solvent to prepare A resin solution;
(b) milling and dispersing a dye or a pigment in an organic solvent to prepare a dispersion;
(c) mixing the resin solution and the dispersion together to prepare a mixture, and removing the solvent from the mixture, thereby to prepare a master batch;
(d) adding an additive to the master batch to form a second mixture, and kneading the second mixture to a compo-sition; and (e) crushing the composition to toner particles.

15. The method as claimed in claim 14 wherein the master batch contains the dye or pigment in an amount of 0.5-10 parts by weight in relation to 100 parts by weight of resin.